Duplex motive transmission for vibratory elements



July 30,1929. G. F. B ORKMA N 7 1,722,656

DUPLEX MOTIVE TRANSMISSION FOR VIBRATORY ELEMENTS Filed Aug. 25, 1926 G. BOEKMAA/I Patented July 30,1929.

UNITED STATES arr GEORGE E. BORKMAN, OF SALT LAKE CITY, "UTAH.

DUPLEX MOTIVE TRANSMISSION FOR VIBRATORY ELEMENTS.

Application filed August 23, 1926. Serial No. 130,920.

This invention relates to a duplex motive transmission for vibratory elements, and its principal objects are: i

First. To provide a connection or transmission from the oscillating, armature, to the diaphragm of a so-called loud speaker, which shall cause the produced or reproduced tones to be mellowed and enriched.

Second. To make use of the maximum dynamic effect of the armature, upon the diaphragm.

Third. To eliminate foreign noises or hissing due to the switching of the free end of the armature, which objection exists in the usual armature mounting.

Fourth. To secure a counterbalancing of the armature, whereby the hammering effect of the armature upon the diaphragm, shall be rendered less intense than is usual.

Fifth. To make possible the use of extremely light material for the armature whereby the latter is rendered more sensitive.

Sixth. To make possible the use of very light diaphragms with the assurance of sufiicient mechanical strength to withstand the motive forces. I 7

Seventh. To make possible an extremely high frequency of vibration in a radio loud speaker or other similar instrument.

Eighth. To secure the previously stated advantages by a device which shall be sim-' ple, durable and economical to manufacture.

The invention herein disclosed, is an improvement on and a continuation in part of the one forming the subject of my other pending application for U. S. patent filed April 11, 1925, Serial No. 22,474, which became abandoned September 1, 1926.

In attaining the objects previously outlined, I provide a duplex connection between the armature and diaphragm, instead of the single connection ordinarily used.

My duplex connectioncomprises a direct or primary member or stylus and a secondary or auxiliary member or stylus. The primary member extends from one end of the'armature to substantially the center of the diaphragm,

from both ends of the armature, instead of from one end only as is ordinarily the case.

Obviously, the capacity for transmitting of vibrations is materially increased by the fact that the primary energy values from one end of the armature and the secondary energy values from theother end of the armature,

are simultaneously conducted to the center phragm, caused by the switching thereof, are I eliminated. This arrangement makes possi-" ble the very desirable condition of simultaneously transmitting'vibrations of different tonal pitches. The arrangement also permits the use of lighter material in the manufacture of the diaphragms, with the assurance at the same time, of having sufficient mechanical strength in the diaphragms to withstand the battering of the motive forces. The hammering on the diaphragms by the armatures, is

less intense by the fact ofthe counterbalancing influence of the transmission.

The features of this invention for which the protection of letters patent is desired,

are collectively grouped in the claims coneluding this specification.

In the drawing, which illustrates several specific embodiments of this invention as appliedto a radio loud speaker:

Fig. 1 represents a plan of a radio loud integral part thereof:

Fig. 2, a section on line 22, Fig. 1; Fig. 3, an elevatlon as seen 1n the threespeakeriunit, partly in'section on line 11, Fig. 2, showmg the present invention as an tion of arrow 3 in Fig. 2, a small part being shown broken away to reveal afragmentary section taken on line 33, Fig. 1;

Fig. 4, a fragmentary section showing a modification in the construction and arrangement of the motive transmission.

Fig. 5, the sameas Fig.4, but showing still another modification, this specific form being shown in my application Serial No. 22,414 previously mentioned herein; 7

20 indicates the permanent magnet, 21 the cap, 24 the base, 25 the pole pieces and 26 the eleetro-inagnetic coil of a radio loud speaker which in general is similar to well-known types. The diaphragm 27 is mounted as usual in the space between the base and the cap, be-

.ing clamped between the resilient gaskets.

The armature 28, in the present instance,

is eccentrically mounted between its ends, on

the pins 35secured in the sleeve 29 of the spoolof the electro-magnet, in accordance with my pending application for U. S. patent filed March'31, 1926, Serial No. 98,835, although a centrally pivoted armature of the ordinary type might be used if desired.

The armature is connected to the diaphragm by means of what I have chosen to term the duplex motive transmission pin or yoke, or simply transmission. This trans mission consists of the substantially straight primary part 30, and the bent auxiliary. part, made up, in this instance, of the branches 30 1 and 30-2, the two branches being joined to each other by an elbow bend 303.- The part 30 is connected to the branch 302 by the crook or neck 30-4, which latter is offset for convenience in connecting the transmission to the diaphragm. This connection is made preferably by soldering to the insert 31 in accordance with my pending application for U. S. patent filed March 31, 1926, Serial No. 98,938. If desired, however, the connection between the transmission and the diaphragm could be made in any other suitable manner. The duplex transmission pin, as just described, is designed to be made of a single piece of light wire, the ends of which may be rigidly secured to the armature 28 in the manner indicated at 32 and 34, Figs. 2 and 6. In the present instance, the armature has an oscillating motion, as indicatedby, the double pointed arrow 36.

The peculiar action of my novel duplex transmission pin may be clearly visualized from Fig. 6. In this figure it. will be seen that the section of the armature together with the duplex transmission pin, form a polygon, which in this instance, has a substantially rectangular configuration. I If, for the moment, we suppose the rec- 35, with the radius 372. However, the rectangle is not rigid,'but on the contrary is flexible, and the diaphragm 27 is fixed cir- The action ofthe bent part, or. L-shaped member, of the duplex transmission pin is quite different, for the reason that the branch 30-1 may be consldered'as a cantilever beam rigidly fastened at 34, or the head of the L,

to the armature, and the branch 30-2 may be considered as another cantilever beam rigidly fastened at its left end to the diaphragm, I

the outstanding ends of these two resilient cantilever beams being preferably integral with each other. Thus it will be seen that The part 30 forms vir- V when the armature is vibrated, motion will be transmitted from its right-hand end through the resilient cantilever beams in a most easy, swaying manner.

The motive force impressed upon both ends of the armature is simultaneous, but owing to the resiliency of the bent or auxiliary part of the duplex transmission pin, the transference of that part of this impress which passes through the said bent or auxiliary part, requires a slightly longer period of time, thus causing a lag in the corresponding tone im press upon the diaphragm and bringing about an auxiliary or overtone condition, which mellows and rounds out the primary or direct 7 tone impress conveyed to the diaphragm through the direct connection. 7

While the duplex transmission pin or yoke is preferably made all in one piece, as previously described, yet it could be made of separate pieces, for instance the two shown at 38 and 39 in Fig. 7.

i The shape and arrangement of the bent or auxiliary member of the duplextransmission pin, influences the nature of the auxiliary tonal impress upon the diaphragnnand offers a wide latitude for meeting various tonal requirements. a i

Theshape of the auxiliary part 401' of the duplex transmission pin shown in Fig. 4, be-

ing more direct, renders'it not so resilient as the auxiliary part of the pin shown in Figs.

2 and 6, and hence the tonal impressupon the diaphragm caused by the part 40 1", would result in tones not as ous instance.

The form ofv the duplex transmission pin in Fig. 5, has given satisfaction but, obviousl is not uite so advanta eous from the manufacturing standpoint as the ones previously described. dicates the pr mary part. 4l-1 and 4I-2 mellowas in the previ In this construction, 41 in- I branches of the auxiliary part, and 41-3 the connection to the diaphragmn The quality of the tones transmitted by the auxiliary member of the duplex transmission pin, may be easily demonstrated in practice, by cutting the primary member through at some point such as indicated by the arrow 42, Fig. 6, between its upper and lower ends. In this way it is found that the auxiliary member of the transmission, causes the diaphragm to give forth the same sounds as are caused by the primary member of the transmission, but in a more subdued manner, producing a lessened tone volume.

By combining the salient features of the present invention with the salient features of my eccentrically pivoted armature, applica tion Serial No. 98,835 previously mentioned a particularly advantageous result is made possible in the production and reproduction of sound values.

\Vhile several specific embodiments of this invention are herein shown and described, it should be clearly understood that all the detailed parts thereof, may or may not appear in the preferred forms, and also, that the pre ferred forms may be varied from time to time, depending upon the circumstances and conditions governing and governed by, the development of this invention and the arts to which it is incident, therefore the scope of this invention may be ascertained from the claims in which its spirit is generalized.

Having fully described my invention, What I claim is 1. In a duplex transmission, a motive memher, a vibratory member, a substantially straight primary transmission member, extending from said motive member to said vibratory member and a substantially L-shaped secondary transmission member extending from the said motive member to the said vibratory member, the point of fastening of the said transmission members to the motive member being separated from each other, and the point of fastening of the said transmission members to the vibratory element being one and the same.

2. A motive member, a vibratory element and a transmission extending from said motive member to said vibratory member, the said transmission comprising a primary column member and an auxiliary resilient beam member separate and distinct from said column member.

3. A motive member, a vibratoryelement and a motive transmission extending from said member to said element, said transmission comprising a primary member lying substantially in a straight line and an auxiliary member lying in other than a straight line; said auxiliary member being separate and distinct from said primary member.

4. A motive member, a Vibratory element and a motive transmission extending from the said member-to said element, said transmission comprising a primary connection substantially in a straight line andan auxiliary connection in substantially an L-shape, the auxiliary connection being operative to lag its delivery slightly in relation to the delivery from the primary connection.

- 5. An oscillating motive member, a diaphragm, a primary transmission member extending along substantially a straight line spective transmission members to the said dia-.

phragm.

7. An armature pivotally supported between its ends, a diaphragm, a column transmission member attached to one end of said armature, a substantially L-shaped transmission member having its head attached to the other end of the armature, and means for fastening the foot of the column member and the toe of the L-shaped member to the said diaphragm.

8. An armature pivotally supported between its ends, a diaphragm, a transmission member lying substantially in a straight line from one end of said armature to the center of said diaphragm, and a second transmission member extending from the other end of said armature to the center of said diaphragm, the said second connection lying in other than a straight line.

9. An armature pivotally supported be tween its ends, a diaphragm, and a motive transmission extending from said armature to said diaphragm, the said transmission be ing composed of a primary connection lying substantially in a straight line and an auxiliary connection having an L-shape, the delivery from the auxiliarylagging slightly in relation to the delivery from the primary.

10. A movable armature e'ccentrically mounted relatively to its ends, a diaphragm, a transmission member extending from one end of said armature to the center of said diaphragm, a second transmission member extending from the other end of said armature to the said center, and meansfor fastening both said transmission members to said diaphragm.

11. A movable armature eccentrically mounted relatively to its ends, a diaphragm, and a transmission extending from said armature to saiddiaphragm, said transmission comprising a column member attached to one end of the armature and a beam member attached to the other end of said armature, the column member and the beam member having a common point of attachment to said diaphragm.

12. A movable armature eccentrically niountedrelatively to its ends, a diaphragm, a primary connection at one end of said arma- 10 ture, an auxiliary connection at the other end of said armature, and'means for fastening both said conne-etlons to a common point in said armature, said connections being so arranged that the delivery from the auxiliary shall lag slightly in relation to the delivery from the primary. I t

In testimony whereof I sign-my name hereto.

GEORGE F. BORKMAN. 

